This invention deals with character holders for photocomposing machines in which the characters are arranged on the holder by rows along with associated position markings.
Such character holders normally are formed on a round glass disc upon which the characters are positioned in arch-shaped rows. Corresponding to the letters, apertures are included which indicate the character size and determine the distance which they are to be set apart. A metallic stop element is located in the center of the disc, which is equipped with a handle for the manipulation of the disc, to adjust and lock the disc on photocomposing machine for operation.
This known character holder is especially disadvantageous in that the areas in which the characters are arranged are open to the environment and as a result could be touched accidentally by operating personnel, and especially when the disc is inserted or removed from the photocomposing machine. The spoilage which thus results, especially through fingerprints, frequently are not removed carefully prior to actual photocomposing, so that, very often the disturbing marks appear in the final print product, which can necessitate that the defective work be repeated. In addition, the round character holder is especially fragile if it is produced from a breakable material, such as glass.
The state-of-the-art also shows a character holder in which the letters are arranged on a film tape which is positioned around a drum (DT-PS No. 365,131). Specifically this drum is defined by a circle of tension bolts which are vertically standing on a drum disc, so that, an open sided drum is created. The drum can carry one, two or more film tape rows located side by side thereon.
Apart from the fact that this drum cannot be easily changed, the externally located film tape is thus greatly exposed, and one must consider the unintentional touching of the area which carries the characters. Furthermore, the continuous film tape that is looped around the drum can expand over the course of time so that a sharp character image is not guaranteed to be produced. Moreover, during the production of this character holder or during a possible exchange of film tapes onto the drum special care has to be taken so that the characters are produced thereon only in the area between the stretching bolts. This character holder, therefore, did not succeed in the industry.
Another character holder for photocomposing machines also consists of a character tape which can be wound and unwound between two drums (DT-PS No. 439,668).
This character holder also has the disadvantage in that the character tape can be easily soiled through unintentional touching, which cannot be easily corrected. In addition, one has to fear a deterioration of the print quality produced therefrom over a period of time because of the tape windings, which can shift with respect to each other on the drums and produce scratches.
The present invention therefore has an object to create character holders for a photocomposing machine in which the character holding parts are extensively protected against unintentional touching, and most of all by which all fingerprints can be avoided as well as marks, such as scratches. In total, the desired character holder should make it possible to obtain high print quality over a long period of time. Finally, the character holder should be easy to change.